2+2=4
Your mother loves you.
Death is a part of life.
The sky is blue.
Truth PowerPoint
What do we mean
when we say we
“know” something?
Ex. “I know my car is in
the parking lot.”
If P is any proposition, what requirements must
we meet to claim P?
a) We must believe that P is the case
(knowledge implies belief, but belief
does not imply knowledge-assumption
b) We have evidence for justification or
warrantability (sufficient reason for
belief … how much is enough?)
c) Knowledge requires truth!
Knowledge is warrented, true belief. To
understand knowledge, we must understand
warrantability and truth.
Modes of Warrantability
 Logical warrantability – laws of logic
 Semantic warrantability – analyzing the meaning of words
 Systemic warrantability – derive warranty from logical
interdependence of all propositions in a deductive system
 Empirical warrantability – confirmatory relation to specific
qualities of first person experience, sometimes
conformation
needed outside self
 Warrantability does not imply truth
 Warrantability = justification and evidence
 Warrantability comes in degrees, truth does not
What is Truth?
•Truth is closely
connected to
knowledge and
belief
•“The
contemplation of
truth and beauty is
the proper object
for which we were
created” William
Hazlett
I.
The Correspondence
Theory of Truth
 Most popular theory of truth
 Plato, Aristotle & Aquinas
 Truth is an agreement
between a proposition and a
fact
 Bertrand Russell (1872-1970)
states that there is a realm of
facts that exists independent
of us (e.g. Toronto is the
capital of Ontario) … “the
truth” of a belief depends on
whether the belief
corresponds to the
independent fact
Critiques of the
Correspondence Theory
 Critics ask “what is a
fact ?”
 Assumes that we
know our experience
of things and also
facts about the world
II. The Coherence
Theory of Truth
 Adherents include Leibniz,
Spinoza and Hegel
 A statement is true if it is
consistent with other
statements that we regard
as true
 Brand Blanchard (18921989) said that “an
agreement between
judgments is best
described not as a
correspondence but as a
coherence.”
 Geometry constructs an
entire system of truths by
building on a few basic
axioms
Critique of the
Correspondence Theory
 Does not distinguish
between consistent truth
and consistent error
 A judgement may be true if
it accords with other
judgments, but what if
other judgments are false?
 Result is a system of
consistent error
 What does the first
judgement cohere with?
III. The Pragmatic Theory
 Pragmatism develops in the
west …. William James
(1842-1910) and John
Dewey (1859-1952) …if
something works it is true !
 There is no absolute truth
… truth is dynamic
changing, subjective and
relative
 See if the belief satisfies the
whole of human nature over
a long period of time
 A statement is true if people
can use it to get the results
that they need
Critiques of the Pragmatic
Theory of Truth
 Critics argue that
truth depends on
the fallible
judgments of
human communities
… unacceptable
 If truth is not
absolute but
relative, who is to
decide what is true
and what is not?
Cartoons on Truth
The Instrumentalist View
 Related to the Pragmatic
Theory of Truth
 Scientific Theories are
true if they enable us to
accurately predict what
will happen ...they work !
 No one believed that
Copernicus’ theory was
an accurate description
of the solar system but it
explained the motion of
the celestial spheres
The Realist View
 Related to the Correspondence Theory of
Truth
 Scientific theories are true or false in so far as
they describe what really exists
 The goal of science is to explain the world as it
really is
 The scientist “discovers” the scientific truth
The Conceptual Relativist
View
 Related to the Coherence
Theory of Truth and the work
of Thomas Kuhn
 A true scientific theory
coheres with the conceptual
framework accepted by a
community of scientists
 Our theories about reality
influence what we think we
are seeing when we observe
reality reality ….we cannot
independently know the real
world